<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      window.onload = function () {
        let btn = document.querySelector('button')
        let timer = setTimeout(function () {
          console.log('Hello~')
        }, 5000)
        btn.addEventListener('click', function () {
          clearTimeout(timer)
        })
      }
    </script>
    <button>点击停止</button>
  </body>
</html>
